We’re fascinated by the bizarre beliefs of those who lived long ago. To learn that people once thought the Earth was flat. To see old maps that depicted dragons and mysterious lands where giants might roam freely. We look at these old beliefs and shake our heads, so secure in the knowledge that we have come so far. In some ways, though, the things we believe today are as far off the mark as those old maps. Consider a new poll from Gallup that shows that Americans think 23% of the population is either gay or lesbian. That’s not an...